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75 lines
2.3 KiB
C++
75 lines
2.3 KiB
C++
/**
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* @file BasicLinearTransforms.cpp
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* @brief Simple program to change contrast and brightness
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* @author OpenCV team
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*/
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#include "opencv2/imgcodecs.hpp"
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#include "opencv2/highgui.hpp"
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#include <iostream>
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// we're NOT "using namespace std;" here, to avoid collisions between the beta variable and std::beta in c++17
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using std::cin;
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using std::cout;
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using std::endl;
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using namespace cv;
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/**
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* @function main
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* @brief Main function
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*/
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int main( int argc, char** argv )
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{
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/// Read image given by user
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//! [basic-linear-transform-load]
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CommandLineParser parser( argc, argv, "{@input | ../data/lena.jpg | input image}" );
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Mat image = imread( parser.get<String>( "@input" ) );
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if( image.empty() )
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{
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cout << "Could not open or find the image!\n" << endl;
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cout << "Usage: " << argv[0] << " <Input image>" << endl;
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return -1;
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}
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//! [basic-linear-transform-load]
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//! [basic-linear-transform-output]
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Mat new_image = Mat::zeros( image.size(), image.type() );
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//! [basic-linear-transform-output]
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//! [basic-linear-transform-parameters]
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double alpha = 1.0; /*< Simple contrast control */
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int beta = 0; /*< Simple brightness control */
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/// Initialize values
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cout << " Basic Linear Transforms " << endl;
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cout << "-------------------------" << endl;
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cout << "* Enter the alpha value [1.0-3.0]: "; cin >> alpha;
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cout << "* Enter the beta value [0-100]: "; cin >> beta;
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//! [basic-linear-transform-parameters]
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/// Do the operation new_image(i,j) = alpha*image(i,j) + beta
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/// Instead of these 'for' loops we could have used simply:
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/// image.convertTo(new_image, -1, alpha, beta);
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/// but we wanted to show you how to access the pixels :)
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//! [basic-linear-transform-operation]
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for( int y = 0; y < image.rows; y++ ) {
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for( int x = 0; x < image.cols; x++ ) {
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for( int c = 0; c < image.channels(); c++ ) {
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new_image.at<Vec3b>(y,x)[c] =
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saturate_cast<uchar>( alpha*image.at<Vec3b>(y,x)[c] + beta );
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}
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}
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}
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//! [basic-linear-transform-operation]
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//! [basic-linear-transform-display]
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/// Show stuff
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imshow("Original Image", image);
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imshow("New Image", new_image);
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/// Wait until user press some key
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waitKey();
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//! [basic-linear-transform-display]
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return 0;
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}
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